I love that it's free! It can't really have too many downsides, other than possibly having to do with your business model/needs (if you're not looking for something entirely cloud-based). The service is great at protecting against attacks from external sources - especially when compared side by side vs Cloudflare or another 'better' solution provider out there like Braintree etc., which often cost quite significantly more per month once they've been acquired by larger companies such as PayPal &